/* stack of pointers
   Copyright (C) 2004 Free Software Foundation, Inc.

This program is free software; you can redistribute it and/or modify it
under the terms of the GNU General Public License as published by the
Free Software Foundation; either version 2, or (at your option) any
later version.

This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details.

You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, 59 Temple Place - Suite 330,
Boston, MA 02111-1307, USA.  */

#include "config.h"
#include "system.h"
#include "coretypes.h"
#include "ptrstack.h"

#define DEFAULT_PTRSTACK_SIZE 256

/* Create empty stack.  */
ptrstack
ptrstack_create (void)
{
  ptrstack stack =
    xmalloc (sizeof (struct ptrstack) +
	     (DEFAULT_PTRSTACK_SIZE - 1) * sizeof (void *));
  stack->prev = stack;
  stack->size = DEFAULT_PTRSTACK_SIZE;
  stack->used = 0;
  return stack;
}

/* Free empty stack.  */
void
ptrstack_free (ptrstack stack)
{
  gcc_assert (stack->prev && !stack->used && stack->prev == stack);
  stack->prev = NULL;
  free (stack);
}

/* Helper function for ptrstack_push - allocate new memory container.  */
ptrstack
ptrstack_grow_internal (ptrstack stack_header)
{
  ptrstack stack = stack_header->prev;
  ptrstack newstack;
  size_t newsize = (size_t) stack->size + (size_t) stack->size / 2;

  if (newsize > 65536)
    newsize = 65536;
  newstack = xmalloc (sizeof (struct ptrstack) + (newsize - 1) * sizeof (void *));
  newstack->prev = stack;
  newstack->size = newsize;
  newstack->used = 0;
  stack_header->prev = newstack;
  return newstack;
}